1. Field of the Invention
The present invention relates to an apparatus and method for displaying 3-dimensional graphics, and more particularly, to an apparatus and method for displaying a region around a position of a mobile object such as a vehicle in 3-dimensional graphics in car navigation or 3-dimensional games.
2. Description of Related Art
Recently, the number of vehicles on the roads has increased, causing increased congestion of traffic. To avoid the congestion of traffic, car navigation systems have been developed. A car navigation system tracks a position of a moving vehicle and accurately displays a region around the vehicle on a road map. Additionally, car navigation systems provide information on a traffic state of other roads or information on, for example, gas stations.
To allow a driver to easily find a desired position on a map of the navigation system, visualization is important. In particular, 3-dimensional visualization is required because a driver can search a 3-dimensional map more conveniently and safely than search a 2-dimensional map while driving fast. Geographical features and buildings displayed in a 3-dimensional form can be instinctively recognized by viewers, thereby providing convenience and safety for drivers.
3-dimensional graphic data may be output in a Virtual Reality Modeling Language (VRML) format, a Moving Picture Experts Group (MPEG) format, or a file format defined by a normal commercial program in an apparatus that outputs 3-dimensional graphic data to a screen. The 3-dimensional graphic data includes geometrical information of objects, e.g., positions of 3-dimensional points of an object and connection of the points; material information of the objects, e.g., texture, transparency, and color of an object, light reflectivity of the object surface, a position and properties of a light source; and information on changes therein over time.
In a conventional method of receiving and displaying 3-dimensional graphic data on a screen, the 3-dimensional graphic data is loaded to memory and data corresponding to a region to be displayed on the screen among the loaded 3-dimensional graphic data is rendered and displayed.
In a first approach of displaying 3-dimensional graphics of a surrounding region changing continuously while a mobile object is moving, after 3-dimensional graphic data of an entire area is loaded to memory, a position of the mobile object is received at each display and only data on a region around the received position among the loaded data is rendered and displayed. However, since the entire 3-dimensional graphic data is very big, a large capacity of memory is needed for a display apparatus. As a result, the first approach has a drawback of increasing manufacturing cost and the size of a system.
In a second approach of displaying 3-dimensional graphics of a surrounding region changing continuously while a mobile object is moving, a position of the mobile object is received at each display, data on a region around the position is loaded to memory, and then the data loaded to the memory is rendered and displayed. However, time is needed to load 3-dimensional graphic data to the memory, and therefore, it is difficult to seamlessly display the 3-dimensional graphics in real time.